1. Field of the Invention
The present invention relates to a semiconductor integrated circuit with multiple power domains and, more particularly, to a domain power notification system that prevents erroneous data from being unknowingly received by one domain when another domain experiences a power condition.
2. Description of the Related Art
In a semiconductor integrated circuit that has multiple power domains that communicate with each other, an interruption in the power supply of a transmitting domain can lead to invalid data being received by a receiving domain. When the receiving domain is unaware that the transmitting domain is experiencing a power interruption, the receiving domain can unknowingly receive erroneous signals from the transmitting domain or random signals from the transmission line. In addition to interruptions in the power supply, a low-voltage condition in the transmitting domain can also lead to invalid data being unknowingly received by the receiving domain.
For example, in a simple two-domain case, a semiconductor integrated circuit can have a 3.3V analog receive domain that receives and digitizes analog signals, and a 1.8V digital processing domain that processes the digitized signals from the analog receive domain. A lost power or low-voltage condition in the analog receive domain can lead to the digital processing domain unknowingly receiving invalid data.
Thus, there is a need for a technique that prevents a domain from unknowingly receiving invalid data when another domain loses power or enters a low-voltage condition.